<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        a {
            text-decoration: none;
            color: black;
        }
        li{
            list-style: none;
        }

       #main #left {
            float: left;
            width: 20%;
            border: 1px solid red;
        }

       #main #right {
            float: left;
            border: 1px solid blue;
           width: 78%;
        }

        .clear:after {
            clear: both;
            content: '';
            display: block;
            height: 0;
        }
    </style>
</head>
<body>
<div id="main" class="clear">
    <div id="left">
        <ul>
            <li><a href="subjects.jsp" target="mainFrame">课程</a></li>
            <li><a href="student.html" target="mainFrame">ajax方式查看学生</a></li>
            <li><a href="studentServlet" target="mainFrame">学生信息</a></li>
            <li><a href="addstudent.jsp" target="mainFrame">添加新生</a></li>
            <li><a href="#" target="mainFrame">课程</a></li>
            <li><a href="context/a.jsp" target="mainFrame">查看上下文演示</a></li>
            <li><a href="logout.jsp" target="_top">退出</a> </li>
        </ul>
    </div>
    <div id="right">
        <iframe src="welcome.jsp" name="mainFrame" frameborder="0" height="800px" width="100%"></iframe>
    </div>
</div>
<!--<h1>李宗请牛逼,张翔牛逼</h1>
<a href="subjects.jsp">查看课程</a>-->
</body>
</html>